The invention relates to means and methods for controlling the cooling of the resultant strand in a continuous casting installation.
It is known to partition into segments the cooling means for the cooling of a strand during continuous casting. What is known as a cooling curve, i.e. a target cooling of the strand depending on strand speed, i.e., casting speed, is thereby allocated to each strand segment. By measuring the strand speed, the optimal target cooling of the strand in the region of a cooling segment is determined via the cooling curve, and the quantity of cooling agent (e.g. the amount of water, given water spray means for cooling) is set corresponding to this target cooling. In this way it is possible to cool a strand acceptably given a constant strand speed or, respectively, given a strand speed that is changes relatively slowly. However, these ideal conditions are not always present. Rather, during operation, more rapid changes in the strand speed can occur such that the cooling is no longer acceptable using the known method. This applies in particular under the condition that the strand speed is strongly dependent on operational demands, such as for example the supply of the casting material.
German patent DE 44 17 808 A1, fully incorporated herein by reference, discloses a method for continuous casting of a metal strand, whereby a strand with a liquid core enclosed by a strand shell is drawn out of a cooled open-ended mold, and is supported in a strand support means downstream from the open-ended mold and is cooled using a cooling agent. In order to take into account changes in the thermodynamic state of the strand, such as changes in the surface temperature of the center temperature of the shell thickness, and also the mechanical state, such as the deformation behavior, etc., these are constantly included in a mathematical simulation model through solution of a heat conduction equation. Thus, the cooling model disclosed in DE 44 17 808 A1 is an inverse cooling model, i.e., a cooling model that calculates the cause (quantity of cooling agent) dependent on the effect (temperature). In a procedure of this sort, the heat equations are solved. However, there is a limit in the degree, i.e, the depth of a possible modeling of the actual heat relationships in the strand. This limitation of the depth of the model significantly restricts the precision in the calculation of the strand temperature.